diff --git a/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/blob.json b/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/blob.json
index cb824822a92b..ae5c2af44c88 100644
--- a/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/blob.json
+++ b/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/blob.json
@@ -923,11 +923,12 @@
             "modelAsString": true
           },
           "description": "The ImmutabilityPolicy state of a blob container, possible values include: Locked and Unlocked."
+        },
+        "allowProtectedAppendWrites": {
+          "type": "boolean",
+          "description": "This property can only be changed for unlocked time-based retention policies. When enabled, new blocks can be written to an append blob while maintaining immutability protection and compliance. Only new blocks can be added and any existing blocks cannot be modified or deleted. This property cannot be changed with ExtendImmutabilityPolicy API"
         }
       },
-      "required": [
-        "immutabilityPeriodSinceCreationInDays"
-      ],
       "description": "The properties of an ImmutabilityPolicy of a blob container."
     },
     "ImmutabilityPolicyProperties": {
diff --git a/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersGetImmutabilityPolicy.json b/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersGetImmutabilityPolicy.json
index 30ee5585ffb0..bdab4c01cd61 100644
--- a/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersGetImmutabilityPolicy.json
+++ b/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersGetImmutabilityPolicy.json
@@ -17,6 +17,7 @@
         "etag": "\"8d59f828e64b75c\"",
         "properties": {
           "immutabilityPeriodSinceCreationInDays": 5,
+          "allowProtectedAppendWrites": true,
           "state": "Unlocked"
         }
       }
diff --git a/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersPutImmutabilityPolicy.json b/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersPutImmutabilityPolicy.json
index 45bacfdedad6..7ede7c161bab 100644
--- a/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersPutImmutabilityPolicy.json
+++ b/specification/storage/resource-manager/Microsoft.Storage/stable/2019-06-01/examples/BlobContainersPutImmutabilityPolicy.json
@@ -9,7 +9,8 @@
     "monitor": "true",
     "parameters": {
       "properties": {
-        "immutabilityPeriodSinceCreationInDays": 3
+        "immutabilityPeriodSinceCreationInDays": 3,
+        "allowProtectedAppendWrites": true
       }
     }
   },
@@ -22,6 +23,7 @@
         "etag": "\"8d59f830cb130e5\"",
         "properties": {
           "immutabilityPeriodSinceCreationInDays": 3,
+          "allowProtectedAppendWrites": true,
           "state": "Unlocked"
         }
       }